1. Field of the Invention
This invention relates to exposure control apparatus for cameras, and more particularly to an exposure control apparatus for a photographic camera having a diaphragm mechanism adjustable in accordance with an output signal provided by a digital computer.
2. Description of the Prior Art
In general, the method of adjusting the diaphragm mechanism of a camera by use of an output pulse signal produced from an exposure value computing circuit, the magnitude of the signal being dependent upon the preselected shutter speed, film speed and photometric value, can be realized in an exposure control apparatus employing either a pulse motor, or a direct-current motor associated with a digital-to-analog converter responsive to the output pulse from the exposure value computing circuit. Such exposure control apparatus, however, are not suited for incorporation in cameras because of the awkward size and power of the presently-available pulse motor, or D. C. motor, and the difficult problem of availability of the electric power source suitable therefor. Further, in order to introduce various exposure control parameters into the exposure value computing circuit, there has been provided in most cases, contact makers such as variable resistors and mechanical switches arranged to be operable as the exposure control parameter setting means. For this reason, troubles due to the wearing-out and insufficient contacting of the contact makers are liable to arise.